Muffler



`Yun@ y 1937. E C; HORTON 2,083,516

MUFFLER Fle April 26, 1935 2 Sheets-Sheet 1 INVENTOR @MM/,MMV

June 8, 1937. E. c. HORTON MUFFLER Filed April 26, 1935 2 Sheets-Sheet 2 INVENTOR Iv/rm )farina l BY @w43 M #Q2/QM,

ATTO NEYS Patented June 8, 1937 UNITED STATES PATENT GFFICE g MUFFLER Application April 26, 1935, Serial No. 18,475

10 Claims.

This invention relates to a muffler for an internal combustion engine, and particularly to a mufller construction having suction producing means incorporated therewith.

5 According to the invention, the muflier casing encloses a perforated tube through which exhaust gases pass, the perforations leading to and from expansion chambers around the perforated tube, so that the gases may expand into the 10 chambers and return to effect a muifling action.

A Venturi tube suction producing device, also enl closed within the casing receives exhaust gases from one of the expansion chambers and discharges into an outlet chamber into which the 15 perforated tube also discharges. A pressure responsive valve at the outlet end of the perforated tube is closed when pressure within the tube is low, in order that adequate ow of exhaust gases through the venturi is assured, but is opened 20 When the pressure increased beyond a predetermined degree in order to avoid excessive back pressure in the engine exhaust system.

The pressure responsive valve is controlled by spring means so arranged that greater pressure,

25 of exhaust fluid Within the muffler, is required to effect initial opening of the valve than is required to return the valve in opened position. By this means, thev valve will not partially open by reason of relatively slight increases in pressure 30 not sufficient to maintain it opened, and thus the number of movements of the parts is reduced.

These and other objects and advantages of the invention, including those inherent in the details of the arrangement of parts, will become ap- 35 parent from the following description, which is made with reference to the accompanying drawings, wherein:

Fig. 1 is a diagrammatic view of a motor vehicle, showing the muiiier of the present inven- 40 tion associated with the vehicle engine and suction accessory system;

Fig. 2 is a vertical section taken longitudinally through the muler;

Fig. 3 is a fragmentary side elevation show- 45 ing the valved, or outlet, end of the muffler;

Fig. 4 is an end view of the muler;

Fig. 5 is a fragmentary vertical cross-section taken on a plane passing through the restricted throat of the venturi; and

Fig. 6 is ay Vertical sectional view of valve means shown mounted upon the engine in Fig. 1.

As shown in Fig. 1, the vehicle I has an internal combustion engine Il with exhaust manifold I2, muffler I3, and exhaust pipe I4. 55 vehicle also has suction-operated accessories in- The' cludlng windshield cleaner l and trumpet I6, connected by conduits I1 to a valve fitting I8 mounted on the engine intake manifold which constitutes a source of suction. A conduit I9 extends from the Venturi suction producing means of the muilier to the valve fitting I8. Operation of the trumpet I6 is controlled by electromagnetic valve 2I in the trumpet branch of conduit I'I, the valve 2| in turn being controlled by an electrical circuit 22 which includes a button type circuit breaker 23- mounted on the steering wheel or steering column of the vehicle.

The valve fitting I8 comprises a hollow casing connected by nipple 24 to the intake manifold 25. The casing has an interior tubular portion 25 into which opens passage 21 from the conduit I1, and the upper and lower ends of which constitute Valve seats. Valve 28, guided by casing closure 29, is normally pressed against the upper valve seat by spring 3l to close communication between conduit l1 and 'the passage 32 through which conduit I9 opens into the upper portion of the valve casing. Another valve, 33, guided by a tubular guide member 34 in the lower portion o-f the valve-casing., is normally pressed against the lower valve seat by spring 35.

It will be understood readily that when the degree of suction maintaining within manifold 25 is slightly greater than that in conduit I9, valve 33 will be opened by reason of the pressure differential on the opposite faces thereof, and that valve 28 will be closed for a like reason. Thus fluid (atmospheric air) will be drawn from the accessories I5, I6, during their operation, through conduit I1 into the intake manifold. But when the degree of suction within conduit I9 exceeds, by a predetermined amount, that mainy taining in the intake manifold, the resulting pressure differentials on the faces of the valves will cause valve 28 to open and valve 33 to close, so that during operation of the accessories I5, I6 fluid will be drawn through conduit I1 into conduit I9.

Muffler I3, which embodies means for producing the suction that is effective through conduit I9, comprises a tubular casing 4I with inlet and outlet end walls 42 and 43, respectively, provided with nipples for connection to exhaust manifold I2 and exhaust pipe I4. Extending longitudinally through casing 4I is a tube 44 connected at one end to wall 42 to receive all gases coming from manifold I2, and connected at its opposite end to a partition Wall 45 adjacent end wall 43. Partition wall 45 has a tubular portion 46 in alignment with and constituting an extension of tube 44, and a valve 41 in portion 48 separates the interior of the tube 44 from the space between walls 43 and 45 which is designated outlet chamber 48.

Surrounding tube 44 and terminating short of Walls 42 and 45 is a second tube, 49. Substantially annular wall members 5| at spaced intervals along the tubes serve to separate the latter and to support the tube 49. Thus a series of expansion chambers, designated 52, are formed around tube 44. Multiple perforations 56 through tube 44 are so arranged that exhaust gases may pass from the tube interior into chambers 52 or return therefrom. The end of tube 49 nearest wall 45 is slitted longitudinally and portions 53 thereof are deformed to engage the tube 44. I'his construction provides enlarged openings between the endmost chamber 52 and the chamber designated 54, between the outer surface of tube 49 and the casing 4| and between wall 45 and an annular wall 55. The latter, in the illustrated construction is approximately midway between walls 42 and 45, and serves to provide additional support for tubes 44 and 49.

Arranged longitudinally within chamber 54 is a Venturi tube 51, having its inlet orifice 58 spaced from annular wall 55 and its discharge end 59 extending through wall 45 to discharge into outlet chamber 48. Adjacent the inlet oriiice of the Venturi tube is. a restricted portion having apertures 6| communicating with a suction chamber 62 formed in a fitting 63. The latter surrounds and supports the inlet end of the Venturi tube and has a passage 64 connecting conduit I9 with chamber 62 (Fig. 5). A nipple 65 serves to=join conduit I9 to fitting 63.

Mounted on tubular portion 46 of wall 45 are opposed bearings 66 for pintle 61 upon which Valve 41 is carried. As shown in Fig. 4, the bearings 66 may be retained in place by abutment against end casing wall 43. One end of pintle 61 extends through Wall 43 and carries a lever arm 68, to the free end 69 of which is fastened a coiled tensioned spring 1I. The opposite end of the spring is fastened to a bracket 12 which constitutes a stationary part of the muffler casing.

As shown in Fig. 3 the arm 68 is so related to valve 41 and spring anchorage 12 that when the valve is inopen position (as shown by broken lines in Fig. 3) the line of pull of the spring approaches the axis of pintle 61, or, in other words, the arm 68 approaches dead center position with respect to the spring. Accordingly as the valve approaches closed position, the leverage of the spring is increased.

A stationary stop 13 prevents the arm 68 from reaching full dead-center position, so that the spring 1| is always effective to some extent in urging closing movement of the valve. Closing movement of the valve is limited and determined by movable stop 14. The latter, in the illustrated embodiment, is a part of arm. 68, and of course is movable with the arm and valve. By means of this movable stop, cessation of closing movement of the valve is cushioned and the spring is not relieved entirely of its tension.

In operation of the muilier, exhaust gases or fluids will enter tube 44 moving in the direction of the arrows in Fig. 1. Pulsations of the gases, causing alternate increase and decrease of the fluid pressure in the tube 44, will effect alternate expansion of the gases through apertures 56 into expansion chambers 52 and return into tube 44. Such action will tendto decrease the pressure pulsations in tube 44 and will serve to mufile the accompanying noise.

Upon reaching the exhaust end of tube 44, if the valve 41 is closed, the gases will pass from the endmost chamber 52 through openings 53 into chamber 54 and thence through the Venturi tube 51 and outlet chamber 48 into the exhaust pipe, as indicated by arrows in Fig. 2. Passage of the gases through the Venturi tube will, of course, effect reduction of static pressure at the restricted portion thereof with the result that fluid will be drawn from chamber 62 through the apertures 6|, thus providing the source of low pressure or suction for the operation of accessories I5, |6.

When engine operation is at a low rate, so that the quantity of exhaust fluid is slight, the mode of operation will be as described above. When, however, this quantity is increased, with resultant increase in the pressure within tube 44, the valve 41 which is off-set relative to the axis of pintle 61, may be opened against the resistance of spring 1| to thereby relieve excessive back pressure (pressure within tube 44). By reason of the dead-center relationship of arm 68 and spring 1I when the valve is open, the degree of back pressure necessary to initially open the valve is substantially greater than that necessary to retain the valve opened, and, accordingly, the valve will not be subjected to such frequent opening and closing movement as it might otherwise.

It will be understood that the apparatus herein described is merely illustrative of the inventive principles involved, and that the latter may be embodied in other physical formations without departing fromA the scope or spirit of the invention.

What is claimed is:

1. In a muilier, a perforated tubular member open at one end for receiving exhaust gases, a pressure responsive valve at the other end of said tubular member for opening in the presence of more than a predetermined pressure within said tube, a second tube surrounding the first-mentioned tube and spaced therefrom by plural wall members at spaced intervals along the tubes. a muiiler casing extending about said tubes and valve and defining an outlet chamber beyond the valve and a chamber around the second tube, the end of said last-mentioned chamber adjacent the valve being in communication with the space between tubes, and a Venturi tube having a suction take-olf arranged longitudinally within the lastrnentioned chamber and having its discharge opening into said outlet chamber.

2. In a muffler, a perforated tube open at one end for receiving exhaust gases, a pressure responsive valve at the other end of said tubular member for opening in the presence of more than a predetermined pressure within said tube, an outlet chamber for receiving gases passing by the valve, a plurality of chambers about said perforated tube whereby exhaust gases may pass from the tube through its perforations into said last mentioned chambers and return therefrom through the perforations, and a Venturi tube having a suction take-off, said Venturi tube having its inlet opening communicating with one of said plurality of 'chambers and its outlet opening communicating with said outlet chamber.

3. In a muffler, an elongated tubular casing with an exhaust gas inlet at one end and an outlet at the other end, a wall near the outlet and defining with the casing an outlet chamber, a tube extending from said inlet into the outlet chamber, said tube being perforated, a second free end of the arm and said part will approachV alinement with the pivot means when the valve is tube within the casing surrounding the first tube for defining therewith an expansion chamber, an opening in the second tube adjacent said wall whereby exhaust gases may pass from the expansion chamber into the space between the second tube and the tubular casing, and a'Venturi tube substantially parallel to said tubes disposed in said space and having its inlet end remote from said wall and its outlet end extending through the wall into said outlet chamber, said Venturi tube having an opening at the restricted throat portion thereof and a suction conduit communieating with said opening.

4. In a muilier, an elongated tubular casing with an exhaust gas inlet at one end and an outlet at the other end, a wall near the outlet and defining with the casing an outlet chamber, a tube extending from said inlet into the outlet chamber, 'said tube being perforated, a second tube within the casing surrounding the ilrst tube for defining therewith an expansion chamber, an opening in the second tube adjacent said wall whereby exhaust gases may pass from the expansion chamber into the space between the second tube and the tubular casing, a Venturi tube substantially parallel to said tubes disposed in said space and having its inlet end remote from said wall and its outlet end extending through the wall into said outlet chamber, said Venturi tube having an opening at the restricted throat portion thereof and a suction conduit communicating with said opening, and a pressure responsive valve at the outlet chamber end of the ilrst-mentioned tube for opening in the presence of pressure within the tube of greater than a predetermined degree.

5. In a suction producing muiller, a casing having a passage and a by-passage between its inlet and outlet ends, a venturi with a suction take-off in one of said passages, a butterfly valve in one of said passages, off-center pivot means pivoting the valve to the casing, whereby a predominating pressure on one face of the valve will urge the latter to open, a lever arm connected to the valve, and tension spring means connected at one end to the free end of the lever arm and at the other end to a part of the casing, said part being on the opposite side of the axis of the pivot means from the lever arm and being so disposed relative to the pivot means and lever arm that the in open position. y

6. In a suction producing muilller, a casing having a passage and a by-passage between its inlet and outlet ends, a venturi with a suction take-oil in one of said passages, a valve in one of said passages, oil-center pivot means pivoting the valve and the casing, whereby a pressuredifferential on opposite faces of the valve will urge the valve to open, a lever arm connected to the valve, and spring means connected to the lever arm for urging the valve to closed position, said lever arm approaching dead center position with respect to the direction of pressure of the spring means when the valve is in open position, whereby a materially lesser pressure differential will retain the valve opened than is required to initially open it.

'7. In a muiller, a casing having a passage for exhaust gases, a butterfly valve in the passage, pivot means offset from the center of the valve pivoting the valve to the casing, a lever arm connected to the valve, and a tension spring connected to the free end of the lever arm and to a point on said casing, said point on the casing being on the opposite side of the pivot means from the free end of the lever arm and approaching alinement with the pivot means and said free end when the valve is in open position, and a' stop member movable with the lever arm and engageable with the spring when the valve approaches closed position.

8. In a muffler, a casing having a passage for exhaust gases, a butterfly valve pivoted to the casing for closing said passage, the pivot for the valve being off -center whereby a pressure differential on opposite faces of the valve will urge the valve to open, a lever arm connected to the valve, and a spring connected to the lever arm for urging the valve to closed position, said lever arm approaching dead center position with respect to the spring means when the valve is in open position, whereby a materially lower pressure diil'erential will retain the valve opened than is required initially to open it, and a stop member movable with the lever arm for engaging against the spring to limit the movement when the valve approaches closed position.

9. In a muffler, a casing having a passage for exhaust gases, a butterfly valve for said passage pivoted to said casing, the pivot being offset from the center of the valve whereby a predominating pressure on one face of the valve will urge opening movement of the latter, a lever arm connected to the valve, and tension spring means connected to the free end of the lever arm and to a part of said casing, said part of the casing being on the side of the pivot opposite to the free end of the lever arm and so disposed that when the valve is in open position said part is in Isubstantial I alinement with said fre end of the lever arm and the valve pivot.

10. In a muiller, a casing having a passage for exhaust gases, a butterfly valve pivoted to the casing for closing said passage, the pivot for the valve being off-center whereby a pressure differential on opposite faces of the valve will urge the valve to open, a lever arm connected to the valve, and spring means connected to the lever arm for urging the valve to closed position, said lever arm approaching dead-center position with respect to the direction of pressure of the spring means when the valveis in open position, whereby a materially lesser pressure differential will retain the valve opened than is required to initially open it.

ERWIN C. HORTON. 

